# Multi-DOF Torsion

## Multi-dimensional System to Introduce Robotics and Torsional Dynamics

The Rotary Multi-DOF Torsion Module is ideal to teach principles of robotics and torsional dynamics. You can use it to demonstrate real-world control challenges, such as the effect of flexible coupling between an actuator and a load encountered in complex industrial processes.

The Torsion module attaches to the Rotary Servo Base Unit (SRV02) for teaching 1 DOF torsional dynamics. Adding one or more (up to seven) torsion modules in series allows to expand complexity of the experiments to study 2 DOF or Multi-DOF torsional dynamics. Using this experiment, students learn to:

• model the torsional system from first-principles
• identify the stiffness and the damping of the system
• using a nominal model parameters, design a state-feedback control using Linear Quadratic Regulator (LQR) to control load angle position via flexible coupling
• tune the LQR control in simulation
• implement the state-feedback control on the actual device and evaluate its performance
• compare partial-state feedback and full-state feedback control strategies

In addition to teaching intermediate control concepts, the Torsion Module can be used for research in various areas, including robust control and system identification.

How It Works

The Torsion Module is a rotary torsional system that consists of an instrumented bearing block, which is mounted in a cubic aluminum frame. A shaft is free to spin inside the bearing block and its angle is measured using an encoder. The shaft can be fitted with either a torsional load or a flexible coupling.

The assembly made of one Rotary Torsion module coupled to a Rotary Servo Base Unit constitutes a one Degree of Freedom (1 DOF) torsional system. The Rotary Servo Base Unit lies on its side so that its DC motor and output shaft are horizontal and able to rotate a flexible coupling attached to a rotational load. The torsional load consists of two inertial disc masses, which can be located at different anchor points along their support bar. Up to seven torsion modules can be coupled in cascade to allow for multi-dimensional control problems.

## Quanser-developed Courseware Included

The Torsion module comes with Quanser-developed courseware for 1 DOF experiment. The workbook with exercises, together with quick start resources, a comprehensive User Manual, pre-designed controllers and a system model allow you to get your lab running faster, saving months of time typically required to develop lab materials.

• High resolution encoders to sense the torsion shaft angle
• Variable disc position to achieve different inertia
• Torsion module easily attaches to the Rotary Servo Base Unit
• Can mount multiple torsion modules for multi degree of freedom torsion system
• Easy-connect cables and connectors
• Fully compatible with MATLAB®/Simulink® and LabVIEW™
• Fully documented system models & parameters provided for MATLAB®, Simulink®; LabVIEW™ and Maple™
• Open architecture design, allowing users to design their own controller
 Overall module dimensions (L x W x H) 21 cm x 13 cm x 13 cm Total module mass 1.2 kg Disk weight mass 0.0022 kg Disk weight diameter 3.80 cm Flexible coupling stiffness 1.0 N.m/rad Load support bar length 4.4 cm Load support bar mass 0.21 kg

Topics included in the Quanser-developed courseware:

Modeling Topics

• First-principles derivation (1 DOF Torsion)
• Lagrange derivation (2 DOF Torsion)
• State-space representation (1 & 2 DOF Torsion)
• Model validation (1 & 2 DOF Torsion)
• Parameter estimation (1 & 2 DOF Torsion)

Control Topics (1 & 2 DOF Torsion)

• Vibration control

##### The Torsion module can be also used to teach other topics that are not included in the Quanser-developed courseware.

To set up your Rotary Torsion workstation, you need additional components. Quanser engineers recommend:

 for MATLAB®/Simulink® users for LabVIEW™ users 1x SRV02 Rotary Servo Base Unit 1x SRV02 Rotary Servo Base Unit 1x Q2-USB data acquisition device¹ 1x VoltPAQ-X1 linear voltage amplifier 1x VoltPAQ-X1 linear voltage amplifier Quanser Rapid Control Prototyping toolkit software QUARC real-time control software and one of the following options: - 1x NI myRIO with 1x Quanser Terminal Board for NI myRIO² - 1x NI CompactRIO controller³ with 1x Quanser Q1-CRIO module - 1x NI M- or X-series data acquisition device2,4 with 1x Quanser NI Terminal Board

¹ alternatively, you can use Q8-USB, QPIDe or any equivalent NI DAQ device supported by QUARC
² only 1 DOF Torsion experiment supported
³  NI cRIO-9074, or NI cRIO-9024 with cRIO-9113 or cRIO-9114 chassis
4 NI DAQ device must be supported by Quanser RCP toolkit. Alternatively, you can use Quanser Q2-USBQ8-USB, or QPIDe

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